Handrail drive arrangement for escalators and human conveyor bands

ABSTRACT

A handrail drive arrangement for personnel transport means, especially escalators and human conveyor bands or belts wherein power transmission is carried out by means of an entrainment mechanism which engages with a toothed arrangement located at the underside of a flexible handrail. According to the invention the entrainment mechanism positively couples the advancing run and the return run of the handrail with one another and simultaneously transmits the driving force or motive power to the advancing run and the return run.

mite States Patent 1 Engeier [451 July 31,1973

Inventor:

Karl Engeier, Schlieren, Switzerland lnventio Aktiengesellschaft,i-iergiswil N.W., Switzerland Filed: Feb. 14, 1972 Appl. No.: 226,120

Assignee:

Foreign Application Priority Data Feb. 24, 1971 Switzerland 2699/71 US.Cl 198/16, 198/203, 198/208 Int. Cl 1166b 9/12 Field of Search 198/16,203, 208

[56] Reierences Cited UNITED STATES PATENTS 2,885,057 5/1959 Hansen198/16 Primary ExaminerRichard E. Aegerter Assistant Examiner-Joseph E.Valenza Attorney-Werner W. Kleeman [57] ABSTRACT A handrail drivearrangement for personnel transport means, especially escalators andhuman conveyor bands or belts wherein power transmission is carried outby means of an entrainment mechanism which engages with a toothedarrangement located at the underside of a flexible handrail. Accordingto the invention the entrainment mechanism positively couples theadvancing run and the return run of the handrail with one another andsimultaneously transmits the driving force or motive power to theadvancing run and the return run.

4 Claims, 4 Drawing Figures 1a a e PATENIEU JUL3 1 I975 same 0F 5 1HANDRAIL DRIVE ARRANGEMENT FOR ESCALATORS AND HUMAN CONVEYOR BANDSBACKGROUND OF THE INVENTION The present invention broadly relates to thefield of transport mechanisms and, in particular, concerns a new andimproved handrail driv-e arrangement for escalators and human conveyorbands or the like, wherein the transmission of force or power isundertaken by an entrainment mechanism which engages with a toothedarrangement located at the underside of a flexible handrail.

The purpose of such type drive systems is to drive the handrail arrangedto both sides of and along the conveying path at the balustrades withthe speed and direction of movement of the conveyor means. It isextremely important that the handrail revolves absolutely synchronouslywith the escalator stair-type belt or the human conveyor band, as thecase may be, so as to afford positive support for the traveller duringthe personnel conveying operation.

The state-of-the-art handrail drive arrangements transmit the driveforce or motive power either in a force-locking manner or a positiveorformlocking manner. Belonging to the first classification are thosedrive systems which transmit the drive force by friction. With such typedrives the handrail is trained about the deflection locations at thebalustrade and, in the event that the drive action does not take placeat a deflection location, then such handrail is trained or wrapped abouta drive gear or wheel housed at the base or pedestal of the escalator.With this arrangement the wrapping angle of the handrail about the drivegear or wheel must be as large as possible in order to attain reallygood power transmission. However, the resultant bending loads with thesimultaneous effect of relatively large tension loads, on the one handproduced by virtue of the pre-loading or pre-stress required forfriction drives and, on the other hand, by virtue of the load whichprevails owing to the bearing forces of the travelling public, result indamage to and premature wear of the handrail.

With friction drives working with counter-pressure rollers there is notpresent the tension load resulting from preloading. However, there ispresent a squeezing action which likewise can considerably impair thelongevity of the handrail. The most prominent disadvantage of frictiondrives, however, is predicated upon the fact that owing to aging of thematerial of the handrail as well as the reduction in the contactpressure and the pre-loading'it is possible for slippage to arise, thehandrail then no longer travelling synchronously with the escalator orthe like.

Now in the case of the positive or form-locking drive systems there isno longer present loading of the handrail owing to the pre-stress andsqueezing action, so that eventually there only still appear the loadsresulting from the hearing or support forces of the travelling public.Furthermore, the aforementioned slippage problem is no longer possiblewith such type drive. In a great many instances the handrail isconstructed at its underside in a racklike manner or there are connectedto the underside of such handrail link chains, flexible perforated steelbands or other suitable means. Power transmission takes place by meansof large gear or sprocket wheels forming entrainment mechanisms locatedat the'deflection locations of the handrail. Ac-

cordingto a different construction of drive system the handrail providedat its underside with teeth is driven at the return run by one or anumber of V-belt pulleys in which there is housed an entrainmentmechanism consisting of an endless toothed band. Other variants of thistype drive employ for power transmission purposes a plurality of gearsat the return run and serving as the entrainment mechanisms, or also inorder to obtain a greater length of engagement a toothed band guidedover two rollers or a link chain.

These drive systems possess the drawback that the load resulting fromthe bearing forces of the travelling public completely acts upon theadvancing or forward run. Consequently, considerable friction andtension loads are present at the linear sections and the deflectionlocations of the handrail. Such can lead to premature wear of thehandrail as well as the guideand deflection devices.

SUMMARY OF THE INVENTION Therefore, with the above discussion in mind itshould be apparent that the technology in this art is still in need of ahandrail drive arrangement for conveyor mechanisms of the characterdescribed, and particularly for escalators and human conveyor belts orbands, which is not associated with the aforementioned limitations anddrawbacks of the state-of-the-art constructions. Hence, a primaryojective of this invention is to provide a handrail drive arrangementfor such escalators and human conveyor belts or bands which effectivelyand reliably fulfills the existing need in the art and is not associatedwith the aforementioned drawbacks and limitations of the heretoforeknown constructions.

Yet a further equally important and more specific object of the presentinvention is to provide a handrail drive arrangement capable oftaking-up the loads caused by the bearing forces of the travellingpublic, especially for large-lift escalators and long human eonveyorbands, so that premature wear at the handrails and the guideanddeflection devices respectively is prevented, and thus, operation of thepersonnel escalator or conveyor band can be carried out moreeconomically.

Another significant object of the present invention relates to a new andimproved construction of handrail drive for human transport deviceswhich is relatively simple in construction, economical to manufacture,extremely reliable in operation, not readily subject to breakdown andwear, requires a minimum of maintenance and servicing, and affordspositive and reliable synchronous travel of the handrail with thetransport device proper.

Now in order to implement these and still further objects of theinvention, which will become more readily apparent as the descriptionproceeds, the drive arrangement proposed by this invention provides anentrainment mechanism which positively couples the advancing run and thereturn run of the handrail with one another and simultaneously transmitsthe drive force to the advancing run and the return run.

In order to be able to effectively unload the deflection or turninglocations of the handrail, it is a further aspect of this development toarrange the entrainment mechanism so as to be displaceable, wherebyduring standstill of the drive there is rendered possible a simultaneousdisplacement of the advancing run and return run in the sense ofincreasing the play between the arcuate-shaped individual components ofthe handrail and the deflection devices.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above, will becomeapparent when consideration is given to the following detaileddescription thereof. Such description makes reference to the annexeddrawings wherein:

FIG. 1 is a schematic illustration, in side view, of a personneltransport device designed according to the teachings of this invention,and here shown by way of illustration in the form of an escalator;

FIG. 2 is an enlarged elevational view of the inventive handrail drive;

FIG. 3 is a cross-sectional view of the handrail drive depicted in FIG.2, taken substantially along the line A-A thereof; and

FIG. 4 is a schematic view of the handrail drive depicted in FIG. 2 atthe region of a deflecting location of the handrail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Considering now thedrawings more specifically, it is here mentioned that while for purposesof illustrative explanation the inventive handrail drive will beconsidered in conjunction with an escalator for transporting personnelor humans, it is obviously not to be considered as solely limited tothis environment of use since it has applicability for other types ofpersonnel transport devices, such as for instance the previouslymentioned personnel conveyor belts or bands. A side schematic view of anescalator structure with which the inventive handrail drive arrangementor system has been employed has been illustrated in FIG. 1.

Now in this Figure reference character 1 designates the pedestal or baseof an escalator and at which there is housed a drive 2 of a steppedescalator chain 3. Drive 2 is driven in conventional manner by means ofany suitable and therefore not particularly illustrated electric motor.At the lower region of the pedestal 1 of the drive 2 drives a suitablegear arrangement 5 through the agency of a chain 4. A further geararrangement or transmission 8 is driven via a chain 7 by means of adeflecting gear or wheel 6 located at the upper end of the escalator. Atthe central region of the escalator the stepped chain 3 drives a geararrangement 9. The pedestal l carries a balustrade or handrail support10 about which is trained an elastic flexible endless handrail 11 havingat its undcrface the toothed arrangement or gear teeth 11a as shownquite clearly in FIG. 2. Handrail 11 slides upon guide slide rails 12and 13 secured to the balustrade 10 and defining guideand deflectingdevices or means. A number of drive units 14 housed at the balustrade 10simultaneously drive the handrail 11 at the advancing or forward movingrun 11.1 and the rearward or reverse moving run I 1.2 through the agencyof a respective endless doubletooth belt 15, Le, a belt having teeth 15aat both faces as clearly shown in FIG. 2 and defining an entrainmentmechanism. As will be explained more fully in conjunction with FIG. 4the double-toothed belts 15 can be adjusted by tensioning rolls 16 in insuch a manner that load-relief or unloading of the handrail 11 at thedeflection locations where there is positioned the deflecting means 12is possible. A chain 17 or equivalent transmits rotational moment fromthe gear arrangement 5 to the lower drive unit or drive 4 of thehandrail 11. On

the other hand the upper drive unit or drive 14 has imparted thereto arotational moment from the gear arrangement 8 through the agency of achain 18, whereas the drive unit or drive 14 arranged at the centralregion of the escalator is driven by the gear arrangement 9 through theagency of the chain 19.

Referring now to FIG. 2 there is illustrated therein, on an enlargedscale, details of a drive unit 14 of the inventive handrail drivearrangement as same is employed in conjunction with the escalatorstructure of FIG. 1. Thus it will be recognized a drive gear 21 anddeflecting gear 22 are rotatably mounted upon a base plate 20 of thedrive unit 14. The double-toothed belt 15, defining the entrainmentmechanism, is in meshing engagement by means of its tooth or toothedarrangement 15a, on the one hand with the handrail l1, and on the otherhand, with the deflection gears or wheels 22 and the drive gear 21. Asprocket wheel or gear 23 is fixedly connected with the drive gear 21.By means of the chain 18 there is delivered to the associated drive unit14 the rotational moment required for driving the handrail 11. Referencenumerals 12 and 13 again designate the guide slide rails for thehandrail 11 and defining the guide and deflecting devices. Supports 24are secured to the base plate 20 and at which there are threadablyconnected by means of the nut members 26 one end of the bifurcatedthreaded bolts 25. At the fork-shaped or bifurcated end of eachbifurcated bolt 25 there are rotatably mounted the tensioning rolls 16.Upon loosening the nut members 26 the bifurcated bolts 25 together withthe tensioning or tension rolls 16 can be shifted. Owing to thisarrangement the possibility exists of accommodating the toothedarrangement 15a of the double-toothed belt 15 to the toothed arrangement11a of the handrail 11 at the advancing run 11.1 and the return run 11.2and to tension appropriately the double-toothed belt 15 of each driveunit 14. Additionally, it is possible to improve the load conditionsprevailing at the deflection or turning locations formed by the rails 12of the handrail 11 by displacing the double-toothed belt 15 by means ofthe tension rolls 16. In this connection attention is invited to FIG. 4.

Now in FIG. 3 reference numeral 21 again designates the drive gearrigidly connected with the sprocket gear 23 and which is rotatablymounted upon the base plate 20 of the drive unit 14 and receives itsdriving rotational moment through the agency of the chain 18. Supports27 which are connected to the base plate 20 carry the guide slide rails13 for the handrail 11. The guide slide rails 12 are secured in anysuitable aNd therefore not particularly illustrated fashion to thebalustrade 10 of the escalator. The guide slide rails 13, locatedbetween the deflecting gears or sprocket wheels 22 for instance at theupper region of the drive unit 14 of FIG. 2 and also between thedeflecting gear 23 and the drive gear 21 at the lower region of suchdrive unit, insure that the double-toothed belt 15, while taking intoaccount a minimum play 28, remains in meshing engagement with the teeth11a of the handrail ll. Ribs 13.1 for guiding the handrail 11 arearranged at the guide slide rails 13. For the same purpose the guideslide rails 12 are likewise provided with ribs 12.1 or equivalentstructure. The double-toothed belt 15 is provided with steel inserts orreinforcements 15.1 which insure that it is practically free ofelongation of stretching.

Now in conjunction with the illustration of FIG. 4 there will beexplained the manner in which it is possible by displacing theentrainment mechanism to improve the load conditions at the deflectionor turning locations of the handrail 11. If during standstill of a driveunit 14 the tension rolls l6 and therewith the double-toothed beltdefining the entrainment mechanism are displaced in the direction of thearrows A, then, the advancing or forward run 11.1 and the return run11.2 of the handrail 11 are simultaneously transported opposite to sucharrow direction, i.e., in the direction of the arrows B. Since thedouble-toothed belt 15 as a practical matter does not elongate, asexplained above, this shifting or displacement is transferredpractically without any loss. Hence at the relevant deflection locationthere is present a play 29 between the substantially arcuate-shapedportions of the handrail 11 and the associated guide slide rail 12. Dueto adjustment of this play 29 there prevails at such deflection locationa considerable reduction in the friction between the handrail 11 andsuch guide slide rail 12. Additionally, the tensional load at thissection of the handrail 11 is considerably reduced.

The advantages realized with the-practice of the inventive conceptsreside in the features that owing to the positive or form-lockingconnection between the forward or advancing run 11.1 and the return run11.2 of the handrail 11, brought about by the double-toothed belt 15there is rendered possible displacement of the handrail 1 1 such thatplay can be adjusted at the deflection locations. In this manner thefriction between the handrail 1 1 and the guide slide rails 12 can beappreciably reduced at the deflection locations and the tensional stressor load at such sections of the handrail is considerably reduced. Anincrease in the bearing or load-applying forces of the travelling publicor users of the personnel conveying system cannot impair the thusobtained favorable wear conditions since, owing to the positive orform-locking connection of the forward handrail run and return handrailrun by means of the double-toothed belt 15 which is free of elongation,it is practically impossible to cause any change in this play. Thesimultaneous drive of the advancing run and the return run produces alow specific surface pressure at the force or power transmissionlocations so that also in this regard the handrail is effectivelyprotected. A further advantage of the invention resides in the fact thatespecially in the case of large lift escalators and long personnelconveyor bands or belts the loads caused by the bearing forces of thetravellers are takenup by the inventive drive arrangement anddistributed in such a manner that at the used section of the handrailthere likewise can only arise minimum frictionand tension loads. Hencewith the arrangement of handrail drives depicted in FIG. 3 the bearingforces arising along the used portions of the length of the handrail aredistributed to the three drive units proposed in this exemplaryembodiment. These drive units are preferably arranged at the upper end,the lower end and at the central region of the linear portion of theescalator.

It is within the contemplation of this invention, and depending upon thelift of the escalator or the length of the personnel conveyor band, toemploy one or a number of drive units. The desired load conditions ofall of the important components of the handrail can be likewise decisivefor the selection of the number of drive units. instead of using thetension rolls for adjusting the play at the deflection locations itwould be also possible to displaceably arrange the entire drive.-Furthermore, it is possible, instead of employing a drive with anendless double-toothed belt for driving the handrail, to use adisplaceably mounted gear which is dimensioned such that it likewise cansimultaneously drive the advancing run and the return run of thehandrail.

Furthermore, for the purpose of adjusting the engagement of the teeth,at least one of the deflecting gears 22 can be mounted to bedisplaceable in the direction of the band. Within certain limits itwould also be possible to adjust the play at the deflection locations ofthe handrail 11, even when omitting the tensioning rolls 16, byemploying at least two displaceably mounted deflecting gears 22. Whilefor clarity in illustration there has only been considered the handrailat one lengthwise extending edge of the transport device, it should beobvious that normally a similar handrail arrangement of the sameconstruction as disclosed herein would then be provided at the otherlengthwise extending side of such transport device.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied and practicedwithin the scope of the following claims. Accordingly,

What is claimed is:

l. A handrail drive arrangement for personnel transport devices,especially escalators and conveyor bands, comprising a flexible handrailprovided at its underside with a tooth arrangement, drive means for saidhandrail, said handrail during its travel defining an advancing run anda return run, said drive means including a toothed belt simultaneouslyengaging with the toothed arrangement at the underside of both theadvancing run and the return run of the flexible handrail, said toothedbelt positively interconnecting the advancing run and the return run ofthe handrail and simultaneously transmitting the drive force to theadvancing run and return run, means for displacing said toothed belt,said displacing means comprising support means, a pair of tensioningrolls, a pair of bifurcated means, nut members for displaceably mountingsaid pair of bifurcated means together with said tensioning rolls atsaid support means, each of said bifurcated means rotatably mounting oneof the pair of tensioning rolls, each tensioning roll being arranged ata part of the toothed belt which extends between the advancing run andthe return run of the handrail, said pair of bifurcated means inconjunction with said pair of tensioning rolls simultaneously displacingthe toothed belt and the advancing run and return run of the handrailand in the same direction.

2. The handrail drive arrangement as defined in claim 1, wherein thetoothed belt comprises an endless, essentially non-elongatabledouble-toothed belt containing-steel reinforcement means.

3. The handrail drive arrangement as defined in claim 1, wherein saiddrive means embodies a number of individual drive units which aresubstantially uniformly arranged over the length of the personneltransport device.

being a drive gear for driving the toothed belt, and guide slide railmeans arranged between the deflecting gears at the advancing run andbetween the deflecting gear and the drive gear at the return run formaintaining in meashing engagement the teeth of the doubletoothed beltwith the tooth arrangement of the handrail.

1. A handrail drive arrangement for personnel transport devices,especially escalators and conveyor bands, comprising a flexible handrailprovided at its underside with a tooth arrangement, drive means for saidhandrail, said handrail during its travel defining an advancing run Anda return run, said drive means including a toothed belt simultaneouslyengaging with the toothed arrangement at the underside of both theadvancing run and the return run of the flexible handrail, said toothedbelt positively interconnecting the advancing run and the return run ofthe handrail and simultaneously transmitting the drive force to theadvancing run and return run, means for displacing said toothed belt,said displacing means comprising support means, a pair of tensioningrolls, a pair of bifurcated means, nut members for displaceably mountingsaid pair of bifurcated means together with said tensioning rolls atsaid support means, each of said bifurcated means rotatably mounting oneof the pair of tensioning rolls, each tensioning roll being arranged ata part of the toothed belt which extends between the advancing run andthe return run of the handrail, said pair of bifurcated means inconjunction with said pair of tensioning rolls simultaneously displacingthe toothed belt and the advancing run and return run of the handrailand in the same direction.
 2. The handrail drive arrangement as definedin claim 1, wherein the toothed belt comprises an endless, essentiallynon-elongatable double-toothed belt containing steel reinforcementmeans.
 3. The handrail drive arrangement as defined in claim 1, whereinsaid drive means embodies a number of individual drive units which aresubstantially uniformly arranged over the length of the personneltransport device.
 4. The handrail drive arrangement as defined in claim1, wherein said toothed belt is a double-toothed belt, a base platesupporting said pair of tension rolls, at least four further rollssupported by said base plate, two of said further rolls being arrangedat the adancing run of the handrail and defining deflecting gears,another two of said further rolls being arranged at the region of thereturn run of the handrail, one of said two further rolls being a drivegear for driving the toothed belt, and guide slide rail means arrangedbetween the deflecting gears at the advancing run and between thedeflecting gear and the drive gear at the return run for maintaining inmeshing engagement the teeth of the double-toothed belt with the tootharrangement of the handrail.